The operation of wireless access networks for enabling wireless communication is highly energy consuming. In view of current environmental concerns, increased attention is paid recently to the energy consumption of telecommunications networks.
Various studies have been performed to reduce conventional energy consumption in wireless access networks, e.g. by exploring the option of using sustainable energy sources (Ericsson AB White Paper “Sustainable energy use in mobile communications, June 2007).
With the development of the 3GGP Long Term Evolution (LTE) network, energy saving for the network is also approached in the context of self organizing networks (SON). In a White Paper of NEC, dated February 2009, “NEC's proposals for next-generation radio network management”, energy is considered as a significant part of the operation expenses of a cellular network. It is recognized that the main saving potential resides in using variations in load over time, that allows to switch off parts of the resources, for example during the night. When a complete base station is switched off, other base stations of the access network need to make up for the reduction in coverage area and capacity. This requires coordination between the nodes. A similar use case is described in 3GGP TR 36.902 v9.1.0 “Self-configuring and self-optimizing network (SON) use cases and solutions”.
Once base stations (or one or more cells thereof) have been deactivated, at some point in time these base stations (or cells) may have to be reactivated again. Thus, a decision is required when and/or which base stations or cells need to be activated.
A first solution would be to activate the base stations or cells at a predetermined time. As an example, it can be imagined that fewer base stations need to be active during night time and more base stations need to be active during the day.
Another solution would be to activate all inactive cells adjacent to (i.e. relevant for) a currently active cell when the currently active cell detects a certain traffic load exceeding a threshold or detects a rising traffic load.
There is a need in the art to improve these solutions by determining more accurately which base stations and/or cells should be activated.